What is the best course of action for a 50-year-old female with a 1-year history of worsening menorrhagia (heavy menstrual bleeding) and associated cyclic lumbar radiculopathy symptoms, including S1 sensory loss, that start a few days before her period and resolve when her period starts?

Catamenial Sciatica: Cyclic Lumbar Radiculopathy Secondary to Endometriosis

This patient has catamenial sciatica—cyclic S1 radiculopathy caused by pelvic endometriosis affecting the lumbosacral plexus or nerve roots, and requires urgent pelvic MRI to identify endometriotic lesions compressing neural structures, followed by gynecologic consultation for hormonal suppression or surgical excision. 1

Diagnostic Approach

Immediate Imaging Required

• Obtain MRI of the lumbosacral plexus and pelvis without contrast as the primary diagnostic study to evaluate for endometriotic lesions compressing the S1 nerve root or lumbosacral plexus 1
• The cyclic nature (symptoms starting before menses and resolving with menstrual flow) is pathognomonic for catamenial sciatica caused by endometriosis 1
• MRI lumbosacral plexus is rated as "usually appropriate" (rating 7) for evaluating plexopathy, which this cyclic pattern suggests 1

Key Diagnostic Features

• The temporal relationship to menstruation distinguishes this from typical disc herniation—symptoms worsen during the luteal phase when progesterone peaks and resolve with menses 1
• S1 sensory loss during episodes confirms true radiculopathy rather than referred pain 2
• The 1-year progressive course with worsening menorrhagia suggests advancing endometriosis 1

Pathophysiology

• Endometriotic implants on or near the lumbosacral plexus, sciatic nerve, or S1 nerve root undergo cyclic hormonal changes 1
• During the luteal phase, these lesions swell and hemorrhage, causing direct neural compression 1
• With menstrual onset, progesterone withdrawal leads to lesion shrinkage and symptom resolution 1

Management Algorithm

First-Line Treatment: Hormonal Suppression

Initiate GnRH analogue therapy during days 1-3 of the menstrual cycle to prevent ovulation and eliminate cyclic hormonal fluctuations 1

• GnRH analogues down-regulate gonadotropin receptors with prolonged use, preventing corpus luteum formation and progesterone surges 1
• After 3 months, add low-dose estradiol patch to prevent menopausal symptoms and bone loss if attacks are controlled 1
• After 6 months, trial low-dose estrogen-progestin combination to determine if low-dose progestin is tolerated 1

Alternative Hormonal Options

• Continuous low-dose hormonal contraceptives (avoiding luteal phase) may be effective if GnRH analogues are not tolerated 1
• Avoid cyclic contraceptives or progestin-only methods, as these may exacerbate symptoms 1

Surgical Considerations

• Refer to gynecologic surgery if hormonal therapy fails after 6 months for excision of endometriotic lesions 1
• MRI findings guide surgical planning for lesion localization 1
• Neurosurgical consultation may be needed if lesions involve neural foramina or require nerve decompression 1

Concurrent Menorrhagia Management

Address the menorrhagia simultaneously, as it likely shares the same endometriotic etiology 1

• Pelvic MRI will evaluate for uterine fibroids versus adenomyosis versus endometriosis 1
• GnRH analogue therapy treats both the radiculopathy and menorrhagia 1
• If fibroids are identified, uterine-sparing options include myomectomy or uterine fibroid embolization 1

Critical Pitfalls to Avoid

Do Not Pursue Lumbar Spine Surgery

• Standard lumbar MRI will likely be normal or show incidental findings unrelated to cyclic symptoms 1
• The cyclic pattern excludes typical disc herniation as the primary cause 1
• Operating on the lumbar spine will not address pelvic endometriosis and will fail to resolve symptoms 1

Do Not Delay Imaging

• Progressive neurologic deficits (S1 sensory loss) warrant prompt evaluation 1
• Endometriotic lesions can cause permanent nerve damage if left untreated 1
• The 1-year duration with worsening symptoms indicates advancing disease 1

Avoid Inappropriate Hormonal Therapy

• Do not use progestin-only contraceptives or high-dose progestin, as these may worsen symptoms 1
• Cyclic oral contraceptives perpetuate the hormonal fluctuations driving symptoms 1
• Hysterectomy and oophorectomy should not be considered unless other indications exist 1

Red Flags Requiring Emergency Evaluation

• Development of bilateral radiculopathy (suggests cauda equina syndrome) 3
• New bladder or bowel dysfunction 4
• Progressive motor weakness beyond current sensory changes 4
• Loss of perineal sensation 4

Follow-Up Protocol

• Reassess at 3 months after initiating hormonal therapy to determine treatment efficacy 1
• If symptoms persist despite 6 months of optimal hormonal suppression, proceed to surgical consultation 1
• Monitor for iron deficiency anemia secondary to menorrhagia during treatment 1